1. Field of the Invention
The present invention relates to a coil type unit for wireless power transmission, a wireless power transmission device, an electronic device, and a manufacturing method of a coil type unit for wireless power transmission.
2. Description of the Related Art
In recent times, a wireless power transmission system has been studied to charge a secondary battery embedded in a mobile terminal etc.
In general, the wireless power transmission device includes a wireless power transmission device that transmits power and a wireless power reception device that receives and stores power.
The wireless power transmission device transmits and receives power using magnetic resonance and electromagnetic induction. For this, in recent times, studies and development have been continuously conducted to improve a wireless power transmission distance.
Therefore, there are active studies on reduction of power transmission time as well as maximization of wireless power transmission efficiency between the wireless power transmission device (wireless charger etc.) and the wireless power reception device (mobile terminal etc.). Among them, studies and development of a coil type unit for wireless power transmission in which a coil is provided in a magnetic body formed of a metal or ferrite sheet have been actively conducted.
Here, the coil in the coil type unit for wireless power transmission is a coil that electrically connects a plurality of coil patterns through a via-hole, but the thickness of the coil is increased and there are problems in terms of cost due to the plurality of coil patterns. Thus, recently, a coil (single-layered coil) in which a coil pattern is designed on the surface of a magnetic body in a loop shape has been widely used.
However, in case of the coil pattern designed in a loop shape, since the output wiring coil should pass over the wound coil wiring for electrical connection between an inner end (input terminal) and an outer end (output terminal) of the coil, the overall thickness of the coil becomes double.
Therefore, since the overall thickness of the coil is increased so that there are restrictions on slimming of a wireless power transmission device and an electronic device including the same and wiring forming and bonding processes for electrical connection are added, process costs are increased and manufacturing becomes inconvenient.
Therefore, in order to meet the current trend for thinner devices, there is a need for the development of a thinner coil type unit for wireless power transmission and a wireless power transmission device and an electronic device including the same.